I made some annotations (not grease pencil!). Where is the menu to remove / hide / edit them?
Selecting again the Annotate tool will display a menu in the header. By default an annotation layer called "Note" is used. 

From that menu, the layer visibility can be toggled, as well as adding / removing layers, and changing some little things like the color and the thickness.



Note: if the header is hidden, it can be displayed again using the little downwards arrow at the top margin of the 3D window.





Edit: ᴊᴀᴄʜʏᴍ ᴍɪᴄʜᴀʟ made me realize that there is another, more natural, place where the menu can be found! The 3D viewport's sidebar (aka "the N menu"), under View > Annotations